1.5 Media Types: Twisted Pair, Fiber Optics & Transceivers

🎯 Key CompTIA Network+ Exam Takeaways

• Cat 6 supports 10 Gbps only up to 55 meters; Cat 6a guarantees 10 Gbps up to the full 100-meter channel.
• Single-mode fiber (OS2) has a ~9 µm core and uses lasers for multi-kilometer spans; Multimode (OM4) has a 50 µm core and uses VCSELs for short reaches.
• Plenum (CMP) rated cables must be installed in drop-ceiling air-handling spaces to prevent toxic smoke spread during fires.

Twisted-pair copper cabling remains the primary standard for horizontal workstation connectivity. Cat 5e supports 1 Gbps up to 100 meters, Cat 6 supports 10 Gbps up to 55 meters, and Cat 6a supports 10 Gbps across the full 100-meter distance at 500 MHz.

Fiber optic cabling transmits light pulses through glass strands, completely immune to electromagnetic interference (EMI) and radio frequency interference (RFI). Single-mode fiber (SMF) has a narrow 9-micron core that permits a single ray of laser light to travel up to 40 km.

In data center racks, Direct Attach Copper (DAC) cables provide high-speed 10G/25G/100G interconnections with lower latency, lower power consumption, and lower cost compared to optical transceivers.

⚠️ Common Pearson VUE Exam Traps

• Using multimode fiber (limited to ~400m at 10G) for campus inter-building spans exceeding 500 meters.
• Mixing up T568A and T568B pinouts: T568B assigns White/Orange and Orange to pins 1 and 2, while T568A assigns White/Green and Green.